Preparation And Properties Of The Laruionite Encapsulated Lead Halide Perovskites

In recent years,lead halide perovskites with a formula of APbX₃?A=Cs,CH₃NH₃,CH?NH₂?₂;X=Cl,Br,I?have attracted extensive research attentions owing to their extraordinary optoelectronic properties.They hold great application potentials in energy,display,photodetectors,and lasing fields.However,the limited phase and morphology-control as well as the poor environmental stability severely prohibited their practical applications.Here,we systematically studied the reaction processes during the fabrication of perovskites using the widely adopted ligand-assistant saturation recrystallization?LASR?method.Based on the mechanism understanding,we extended the LASR approach to prepare perovskite@laurionite core-shell structures without introducing any additional chemicals.This is the first report of fabricating perovskite@laurionite core-shell structures.The perovskite structures demonstrated significantly improved environmental stability with slightly improved optical properties after being encapualted by laurionite.The main contents include:1)The relationship between the experimental parameters and the phase/morphology of the perovskite products was studied.The ratio and concentration of the precursors as well as reaction time showed prominent influence on the phase of the perovskites.The underlying mechanism of the influence was revealed.Occationally,we found that laurionite was prepared after long reaction times at high concentrations of lead ions.2)The capability of the ligand-assistant saturation recrystallization method regarding the fabrication of laurionite was evaluated.The relationship between the morphology of the laurionite product and the experimental parameters was built.The morphology of the laurionite microparticles could be accurately controlled.High throughput production of laurionite microparticles was achieved.Conversion of laurionite into pervoskites was realized while maintaining the morphology unchanged.3)Based on the above studies,the ligand-assistant room temperature saturation recrystallization was developed to prepared perovskite@laurionite core-shell structures.The number of the perovskite layer wihin the laurionite shell could be adjusted by varying the amount of CsBr.The photoluminescence could therefore be controlled.Color barcoded perovskite@laurionite microparticles were prepared though controlling the location of the perovskites with different perovskite layers.More importantly,the perovskite@laurionite structures demonstrated strong resistance to air,water,ethanol,irradiation,heat and halide exchange processes.These findings deepen our understanding of the reaction processes during preparation of perovskites using the ligand-assistant saturation recrystallization method.Also,the discovery that laurioniate could spontaneously encapsulate perovskites during room temperature saturation recrystallization processes is of paramout importance to develop environmentally stable pervosktes.